TW201100338A - Control of the bow of a glass ribbon - Google Patents

Abstract

Methods for controlling the bow (shape) of a vertical glass ribbon (13) produced by a downdraw process are provided. The methods involve passing the ribbon (13) through a gas-filled vertical enclosure (23), e.g., a draw tower, whose bottom (31) is open to the atmosphere. The ribbon (13) acts as a septum that divides the enclosure's internal volume (29) into a first sub-volume (25) and a second sub-volume (27). Using the stack effect, a positive pressure difference is produced between the first sub-volume (25) and the second sub-volume (27) along at least a portion of the length of the enclosure (the DDZ). The edges of the ribbon (13) are constrained so that they do not move into the second sub-volume (27) over at least the DDZ. As a result, the ribbon bows with its concavity facing the first sub-volume (25) and its convexity facing the second sub-volume (27).

Description

201100338 VI. OBJECTS OF THE INVENTION: [Priority Claim] The present invention claims the priority of U.S. Patent Application Serial No. 12/486,236, filed on Jun. The overall content is incorporated herein by reference. TECHNICAL FIELD OF THE INVENTION The present invention relates to a glass ribbon body manufactured by a pull-down procedure (e.g., an overflow melting pull-down procedure). More particularly, the invention relates to a method and apparatus for controlling the out-of-plane arc of such a belt, which control may include stabilizing the existing bow or creating a new bow. [Prior Art] As is known, the 'overflow melting pull-down procedure is a primary glass manufacturing process for manufacturing substrates used in display devices; as is known, display devices are used in various applications', for example, thin film transistors Liquid crystal displays (TFT-LCDs) are used in notebook computers, flat panel monitors, LCD TVs, and various communication devices. Many display devices (such as TFT-LCDs and organic light-emitting diode (OLED) panels) are fabricated directly on flat glass sheets (glass substrates). To increase production speed and reduce costs, the typical panel process is 201100338. A plurality of panels are simultaneously fabricated on the substrate. To achieve economies of scale, display manufacturers need larger substrates to create more displays and/or larger displays on individual substrates. The production of larger substrates is a challenge for the glass manufacturing industry, particularly the thickness of the substrate is generally less than i millimeters (e.g., 7 milliseconds), and is currently even less than 0.3 millimeters in some cases.

A particular challenge is the management of the behavior of the glass ribbon in the stretching tower. It is conceivable that when the strip becomes wider and thinner while pulling down the distance above two floors, the strip will undergo complex movements and shapes during cooling. = The required quality of the substrate used for the display device, the quality portion of the tape must be kept neat, so that the area that may be in contact with the tape is limited to the outer edge (bubble portion) of the tape. Based on the inverse considerations, the control of the shape of the strip has become a serious engineering challenge. This problem can be formalized to control the shape of the moving material without touching the middle region of the material, where: (1) the material has the machine 2: the crucible is different from the tissue paper' (li) the material is continuously made with a width of more than two meters. The two ', and (m) materials are subject to complex temperature and stress distributions, which will move the mechanical properties of the ~I ring material. The present invention solves this problem and provides a method of not contacting the quality portion of the belt to form and/or stabilize the out-of-plane arc of the vertical glass ribbon. . SUMMARY OF THE INVENTION In accordance with the present invention, a method for controlling the arc of a vertical glass ribbon (13) made by a pull-down program is provided. The method comprises: (a) passing the strip (13) through an inflated vertical housing (23), wherein: (0) the housing (23) includes a wall (17) defining an interior space (29) (11) the bottom (31) of the inner space (29) is open such that the pressure at the bottom is the pressure of the surrounding atmosphere, and (ill) the strip (13) acts as a partition that houses the housing The internal Q space (29) is divided into a first subspace (25) and a second subspace (27); (b) by (1) in the first subspace of the band (丨3) (25) The average density of the gas on the side is (之间) between the average density of the gas on the side of the second subspace (27) of the strip (13), along the length of the shell (23) a difference obtained above a vertical zone, in the first subspace (25) and the second subspace (27), a positive pressure difference is generated along a length of at least a portion of the casing (23); The density of the flat ridge on the side of the first subspace (25) of the strip (13) is smaller than the average density on the side of the second subspace (27) of the strip (13); and (c) the limit (21) the belt (13) Edges to prevent the edges from moving over at least the vertical region of the second subspace (27). The component symbols used in the above summary are for convenience only, and are not intended to be used and should not be construed In order to limit the scope of the invention, it is to be understood that the foregoing general description and the following detailed description Other features and advantages are described in the following embodiments, which may be understood and practiced by those skilled in the art. The accompanying drawings are intended to provide a further understanding of the present invention, which is incorporated in the specification. It is a part of the invention. The various features of the invention disclosed in the specification and drawings can be used in any or all combinations. [Embodiment] Ο 〇 7 V bar 熔 熔 melting procedure, overflow : Program, or overflow program), it should be noted that the method described in this paper can also be applied to other drop-down glass processes, such as trough stretching systems. As the dissolution apparatus is known in the art, the details are omitted and not sold to avoid obscuring the description of the exemplary embodiment.

As shown in Fig. 1, a typical dissolution apparatus utilizes a forming structure (Isolation I) which contains a transfer tube (not shown) defined by the body 7 to receive the molten glass. . The molten glass is moved twice above the carcass 7 and flows down the outer surface of the isolating tube until the two pieces of glazed glass that reach the converging side of the tube are joined together to form a single unit. Body 13. Downstream of the root, there are a plurality of sets of draw rollers (not shown) that are in contact with the outer edge of the strip and apply tension to the strip to the floor. The controlled rate is pulled away from the root canal to protect the molten glass from contamination 3 and the glass ribbon system is included in the dyeing, and to help control its temperature, in the isolation casing 23, the inner surface of the casing 201100338 contains the coil row The temperature (cooling rate) of the belt is controlled as it passes through the casing (drawing down). The cross-sections shown in Figures 1 and 3 are taken along one of the planes of the depth of the cutting shell (from front to back), the width of the casing (side-to-side) being parallel to the surface of the belt and generally wider than the depth.

Part of the overall procedure 'must separate individual glass sheets from the moving glass ribbon, which generally involves a sc〇ring strip and will be relative to the strip by along the score line The sheet of the surface is bent such that the strip portion (individual glass sheet) under the line of the smear separates from the strand being placed, thereby causing the sheet to break from the strip at the scribe line. Marking and bending are generally accomplished by contacting the side of the strip with a moving anvil, sculpting the other side of the strip, and then bending the sheet along the anvil at the score line to break the strip. The symbol 19 of the i-th figure shows the general position of the sheet separating apparatus, and as shown, the separation occurs under the casing 23. The glass ribbon body is required to be stable by touching the edge of the strip (rather than the center) with the anvil along which the strip will be bent. The smear of the glass begins at the edge and advances to the other edge; during this procedure the edge needs to be on the anvil so that the ribbon does not twist as the stencil squeezes. During the separation, it is preferred that the crack starts at one or both edges and advances toward the center. If the edge touches the station piece when it begins to bend, the area subjected to the greatest stress will also be at the edge, causing the crack to start from there. In the dazzling forming process, the belt body usually has several different shapes of stable money keys. The change of the processing conditions will cause the belt to change between these stable types. The special collection has low effective hardness and thus various U-stability. Type 8 201100338 1. This is especially true for wide and/or thin strips that transition between them. In other positions, the shape of the strip at the separation point can be dynamically changed, and the change in these shapes can be quite large, so that the curvature along the strip will change its sign (sign) as described above. Any or all of the changes are negatively affected by the separation process 'these changes in shape will also affect the product characteristics' in some cases will make the glass piece unacceptable to the customer. Therefore, the strip needs to maintain a stable shape with small changes in time during the process. Q In the dissolution forming process, the shape of the strip at the separation point can be controlled by the manipulation of the strip temperature. However, the temperature must be manipulated above the separation point because the separation device hinders the heating and cooling of the strip and therefore the control strip The practicality of body temperature is limited to some extent. Other strip shape controls are also available through a variety of physical devices (eg, rollers, air bearings, and the like); while effective, devices that are in physical contact with the glass ribbon typically also reduce the operating window of the process, making it small Process variables are more sensitive. In particular, it is a problem to perform clamping on the edge of the belt. In contrast to these conventional modes, the present invention (4) "(4) effect" (see below) obtains a pressure difference between the belts for controlling its arc, or more generally 'controlling its shape. It should be noted that the present invention can be used in conjunction with the shape control techniques previously employed. The techniques of the present invention can also be used with other techniques in a particular application. In general, a wide glass ribbon (supported at its vertical edges and unrestricted at the top and bottom) can be bent by a uniform pressure carried on one side, the edges of which are supported (limited) to the other side. Figure 2 shows the basic geometry 9 201100338. Where 13 is the width, thickness and radius of curvature of the glass ribbon, the displacement of the plane of the limit 21 (also shift). W", "t" and "R" are respectively strips, and "b" is assumed to be unloaded with respect to the maximum plane out of the edge passing through the edge, ie b is the strip, and the strip is obtained from the center of the strip. The amount of reflection is: the pressure difference between the thicknesses is ΔΡ, and

32 and 3 where E is the Young's modulus of the glass ' ^ is the Passon ratio Ratio, and the pressure difference Δ Ρι · 2 is from the concave side of the glass (high side; side 1) to the convex side (low side; side 2 In this formula, it is assumed that the strip is unrestricted at the top and bottom. The above equation can be re-shifted to obtain the pressure load required to obtain a predetermined amount of reflection: 32 levels 3

5w4(l-v2) Equation (2) It is important to show that the pressure required to obtain or stabilize a considerable amount of bow arc (for example, 2 cm in the center) is not large by the following calculation; for example, The following characteristics are taken as examples: Width W 25 00mm Thickness T 0.7mm Young's modulus E 71016Mpa Passon's ratio V 0.23 201100338 Required bow arc B 20mm For these values, ΔΡυ is 〇.〇 84Pa. As will be understood from the discussion below, in accordance with the present invention, this pressure differential and greater pressure differential can be achieved by obtaining a difference in gas density on either side of the strip. It is also like the discussion that the density difference is obtained by the so-called "smoke-effect" phenomenon.

In the following analysis, it is assumed that the belt acts as a partition which divides the internal space 29 of the casing into two sub-spaces 25, 27 (see Figures i and 3). Subspaces generally have the same volume, but can have different volumes if desired. In practice, the strip does not extend along the overall width of the interior space of the housing. As shown in Figure 1, the strip does not need to extend to the overall width of the housing. H gas can flow over the side edges of the strip and above the strip. In this regard, the belt is not a perfect partition, that is, it can be regarded as a part of the partition, but can provide sufficient flow isolation between the sub-turns, thus maintaining a pressure difference (in the scope of this application and the patent application) The term "separator" refers to this part of the partition that is opposite to a perfect barrier. Based on the rule of thumb, the strip should extend along the width of at least about 80% of the interior space of the shell. In the same manner, usually, the wall 17 of the casing 23 is not a perfect wall such as a belt body which can avoid all the flow between the surrounding large rolling and the internal space of the casing 29, and the wall body only needs to provide each subspace. 25, 27 is sufficiently isolated from the surrounding atmosphere to make the subspace and grade. The required pressure is maintained in the workshop. In practice, the gas filled into the two subspaces is generally the same and is 11 201100338 air. However, if it is required for a specific application, it is also possible to use a gas other than air (for example, helium), and the gas on both sides of the belt (separator) may be different, which itself can obtain a pressure difference between the belt bodies. (See discussion of equation (7) below). As shown in Fig. 3, the casing of Fig. 1 can be regarded as a simple casing having a closed top and a bottom open, and is divided into two sides by a glass ribbon body, and each side is filled with a gas. In the following, the first side of the strip (where z < 〇) is referred to as side 1 ' and the second side of the strip (where z > 〇) is referred to as side 2. Note 0 When referring to individual glass sheets separated from the body, side 1 is typically located on the anvil side of the separation device, which has a lower density/higher pressure. When the gas density on each side of the strip is different, the pressure difference will be obtained by the H vac engineer's "smoke effect". A discussion of the effects of chimneys can be found in the document "ASHRAE Fundamentals Handbook" or in Handbook of Air Conditioning and Refrigeration (Second Edition) by Wang, S. (McGraw-Hill, 2001). o According to the chimney effect, the pressure difference between the two sides of the housing can be expressed as:

Ρχ (y) - Pi (y) = s\\pi (y〇- a iy')W ° where (3) where y, g, Pi, P2, p!, P2 are: y: vertical degree coordinates 'It is zero at the bottom of the shell and increases g in the opposite direction of gravity: gravity, ie 9.81m/s2

Pi : pressure on the side 1 of the housing 12 201100338 P2 : pressure on the side 2 of the housing

Pi: gas density P2 on the side 1 of the casing: the gas density on the side 2 of the casing and the pressure at the bottom of the casing (y=〇) satisfies the following conditions: (4) is (〇) = Α (0) 可用 This condition can be used because the bottom of the case is open to the atmosphere. It is known from the formula (3) that if the density on the side 1 is lower than the side 2, the pressure on the side 1 is higher. Since in equation (3), the pressure difference is due to the difference in overall density, it is not necessary to maintain the density difference over the entire height of the casing, but only needs to be maintained on a subset of the overall height; The single or partial housing of the pressure difference between the two sides is called Density Difference Zones or DDZs. For ease of description, unless otherwise indicated, it is assumed hereinafter that the housing has only a single 〇 DDZ 'In fact, it should be understood that the housing may also include a DDZ located above the length of the housing, in some instances, The entire length of the housing can be used as a DDZ. Above the DDZ, the average density difference can be defined as · yt

Tp=y』-_____ y, -yb Equation (5) Here, DDZ starts at height yb and ends at height yt. As noted above, 13 201100338 heights yb and yt can be the bottom and top of the housing. "Using the above equations (1) and (3), we can get the following formula for the difference in average density above the DDZ with bowing amount (called _) b":

Ap: 32bEt3 Equation (6) Ο At the height above the DDZ, there is another DDZ or other belt in the body arch system. The required bow arc is not reached because there is no differential pressure load; 'about 'b', unless the shell is below the DDZ, the strip is depending on the strip characteristics, and the strip will be one below the DDZ. Q "The 々i exhibits a stable pattern at the cross-distance. In some embodiments, DD z can be utilized relative to the manufacture of a new bow 31'

Come stable - existing bow arc. In this case, the direction of the arc is selected to conform to the existing bow. The presence of DDZ reduces the likelihood that the shape of the strip will deviate from the curved state and be converted to another, less desirable form. The shape stability as described above is a specific value which is related to the separation of the individual glass sheets from the strip. In the alternative, ddz may be opposite the pre-existing bow arc, thus helping to switch the strip to another different, more desirable pattern. In this context, the term "controlling the arc of the glass ribbon" covers the above and other applications of the DDZ that affect the shape of the glass ribbon. The required density difference for obtaining the pressure difference for bending the strip may be caused by the composition of the gas on each side of the strip, and therefore, by using gases of different compositions on both sides of the strip, even on both sides The temperature distribution is the same and also 201100338 for different densities. More generally, the temperature difference is used to obtain a difference in density, which in turn results in a pressure differential. In static or pseudo-static gases close to atmospheric pressure, the density is approximately related to the pressure and temperature of the ideal gas law:

PM I — (7)

RT where: gas density Ρ pressure Ρ about 101325Pa = l atmospheric pressure molecular weight 空气 air is 28.8kg / kmol gas constant R 8314J / kmol / K gas temperature Τ if the pressure changes little (as in the case of the stretching tower), the density can be seen It is a function of temperature and composition only. The composition affects the density by the average molecular weight of the gas (i.e., M in the formula (7)). In the following, it is assumed that the composition on both sides of the glass ribbon is the same 'so the density is only a function of temperature. Therefore, the pressure difference between the belts of the formula (7) can be expressed as: (10)) - household 2ω =

gMP-R

y JL^2(y) Φ'\ ¥ (8) where: average pressure Ρ 15 201100338 side 1 gas temperature Tl side 2 gas temperature □ 2 From equation (8), we can see that the difference between the two sides can be borrowed Obtained from the temperature difference between the sides. The temperature difference can be obtained in a number of ways. The simplest method is to electrically heat the side of the strip with a power input higher than the other side, which has the effect of heating the gas on the side of the strip at a higher power. Higher temperature gases are more expensive, so depending on the smoke self-effect, the force is higher than the lower temperature gas. Therefore, the strip will be bent from the higher temperature side to the lower temperature side (i.e., assuming its edge is limited, as shown by 21 in Fig. 2), which faces the concave side and the convex side toward the low temperature side. One example of a temperature difference effect is illustrated in Figures 4 and 5. In these figures and Figures 6-7 and 8_9, the horizontal axis represents the height from the bottom of the housing (in meters), and the right vertical axis represents the pressure difference (Ρ!-Ρ2) (in units Pa), while the left vertical axis represents the temperature difference (T]-T2 in Figures 4 and 8 (the unit is 〇, which represents the density difference (第ι_Ρ2) in the 5th, 7th, and 9th ( (unit It is kg/m3). The solid line in each figure illustrates the pressure difference, while in the 4th, 6th, and 8th figures, the broken line represents the temperature difference, and the lines in the 5th, 7th, and 9th lines indicate the density difference. In these figures The horizontal arrow indicates the vertical axis represented by the solid line and the dotted line. Between the 4th and 9th figures, the gas used for calculation is air with a molecular weight of 28 8kg/km〇1, and other physical properties are available. Standard Reference Basis. For the case of Figures 4 to 5, a higher power is applied to the side turns of the strip to obtain a higher temperature there (for example, in Figure 3,

Tlw(y)>T2w(y), thus TKy^Ky), where Tlw(y) and T2W(y) 201100338 are wall 'degrees' and Tl(y) and T2(y) are gas temperatures), The helium temperature on side 1 is only in the lowermost portion of the housing. Alternatively, a lower power is applied to side 2 or a relative cooling gas is injected into side 2 to achieve a relatively higher average density on this side. Since the pressure is a function of the overall density, even if the temperature difference falls only in the lowermost portion of the casing, once the pressure difference is formed, it extends upward through the end of the casing. This effect is illustrated by the flat portion of the pressure curve in Figures 4 and 5.

The right only needs to have a pressure differential in a portion of the housing, and the difference in density can be reversed over the initial DDZ to obtain a third vertically higher DDz that eliminates the pressure differential in the lower region. This—configuration is shown in Figures 6 and 7. As shown in these figures, the temperature rises about 5 meters per ton (lower DDZ) and then decreases about every i-meter (higher DDZ), and the rise and fall are the same size. Relative to Side 2, the gas density at 4 is reduced in the lower DDZ, causing the relative pressure to rise due to the (IV) effect. In the higher DDZ, the density on side 1 increases relative to side 2, causing the relative pressure to again decrease due to the chimney effect. In this manner, a positive pressure differential between side 1 and side 2 can be obtained over a finite length of the housing. A second way to obtain a temperature difference between the two sides of the housing is to allow the gas to flow on one side or the other, or more generally, to provide a difference in gas flow on both sides. For example, if a hole (aperture) is placed on the side or top of the shell on one side of the strip (rather than the other side), the gas will be on the side (rather than the other side) due to the smoke self-effect. The bottom flows and rises, flowing out of the holes in the side. Again, note that the strip is not a perfect spacer, so there is still gas flow on the side that does not contain the hole, but it must be smaller than the one with holes = 17 201100338. In another alternative, fans, pumps, and / = devices (such as flow controllers) can be utilized to actively adjust the private flow on both sides of the strip to achieve the desired flow rate difference. Ο 〇: How the tube reaches different flow rates, on the side with a relatively high flow: 'Because the power from the glass and the shell structure is required (eg heater coil of the body) to increase the gas temperature, so The gas system there is at a lower temperature. On the non-flow side (or less flow side), the temperature of the gas is souther because no power is required (or lower power is required). The air temperature estimation model on the flow side (assumed to be side 2) is as follows: iTM-^iT2(y)-Tw(y)h〇P Equation (9) where ^^ coefficient h glass and shell wall temperature τ 1 w Gas flow rate % on side 2 Gas heat capacity e Solve T2(y) in this equation 'Get a function of temperature in the flow side as y, and bring it into equation (8) to get the pressure difference between the two sides. If there is also a flow on the side, an equation similar to equation (9) can be applied to this side, and then used in equation (8). Figures 8 and 9 illustrate examples of temperature and pressure differentials that can be obtained from the flow on side 2. The values of the heat transfer coefficient h and the flow rate ^ are / κ and 〇.〇〇lkg/see/m, respectively. As shown, a substantial temperature difference of 18 201100338 and a substantial density difference can be obtained, so that the chimney effect achieves a substantial pressure difference (P0P2) between side 1 and side 2. It should be noted that although it is difficult to directly measure the gas density, indirect measurement can be simply performed to determine whether or not to use DDZ in the drawing tower. Specifically, if the gases on both sides of the strip are the same, the gas density can be calculated by standard methods using the gas temperatures on both sides of the strip. The presence or absence of one or more DDZs can be clearly indicated by the gas density versus height relationship on each side of the housing. In this case, whether or not the gas has a flow. When the gas composition on one side is different from the other side, the density distribution is calculated using the temperature and composition measured at several heights. Specifically, the density is calculated from the temperature and composition data in a standard manner, and the density versus height graph again shows the presence of one or more DDZs. Standard methods for converting temperature measurements to density measurements (or converting temperature and component measurements to density measurements) can be simplified to refer to density tables in most references (eg, air density tables at different temperatures), Or you need to construct such a density meter when using less fully studied gas. Models can be used for this (eg empirical mode). For example, in some cases the ideal gas law can be applied to convert temperature and/or component measurements to density values. According to this application, pressure information can also be incorporated in the density measurement. It should be noted that the chimney effect acts on the opposite direction of the different compressive/tension effects on the glass ribbon, thus causing a temperature difference between the thicknesses of the strips. Importantly, the chimney effect is many times stronger than the pressure/tension effect, and the following analysis illustrates this difference. 19 201100338 According to the following formula, the bow arc can be made by the temperature difference between the strip thickness: 〇cATrw^

Equation (10) where α is the coefficient of thermal expansion (CTE) of the strip material, and Δ Tr is the temperature difference between the strips (the convex side of the hot side ligament). 〇f, Δτ>· is a function of the process conditions. When the air is on each side of the strip and the temperature of the air on both sides is different, the temperature difference between the strips can be expressed as follows:

h h+^ (Ά-Τ2)- h h + k Δ7;- (11) where h is the heat transfer coefficient between air and the strip, and k is the effective thermal conductivity of the strip (including the radiation effect). As described above, the temperature on both sides of the belt is Τ'2' and the thickness of the belt is t. Eliminate the temperature difference between the surface of the strip and obtain: - Δ7; _2 = - m (12) ' Ik, 1+ - , ht j 20 201100338 Therefore, in most production situations, k / ht > gt; AG. k \6b h aw2 (13)

In the actual case, 'k=3.5W/m/0K, =2500mm, a=3.5ppm/K

-2〇w/m2, 〇K size is therefore the temperature difference required to achieve a two-centimeter arc (b = 20mm): Knife k 16b h aw2 2560 rule (14) Effectively beyond the temperature difference The range is 10 times smaller than the temperature difference in the 8 graph. '4, 6, as known from the foregoing, it provides a method for controlling the shape of a strip in a downward stretch, (for example, a melt forming process), which is modified on each side of the strip by utilizing the chimney effect. This control system is achieved by m + dx , too l milk (eg air) * pressure. The pressure is not manipulated by the flow rate oj χ ^ &quot;· but is manipulated by temperature, which changes the gas density and then changes the gravity head of the gas column on the side of the belt to manipulate the displacement. Between the gas temperature and the gas: it is preferred to control the pressure by temperature, for example by electric heating for two turns, or by injecting cold or hot air onto the belt near one side or the other. In fact, the required temperature difference can be easily achieved. Body: = If the roller is arranged along the edge of the strip, the gas pressure can drive the strip against the limit and bend the strip laterally. By using these methods, the shape of the bow can be maintained with a minimum of the physical limit of the band, so that the maximum tolerance process variable can be obtained. In addition, the equipment to perform these methods is relatively simple, inexpensive, and robust. The stability of the tape to the process variables is greater than that achievable in the prior art. From the foregoing description, it will be apparent to those skilled in the <RTIgt; For example, although the above examples assume that the cross-sectional area of the subspace above the length of the draw tower maintains Q constant, the analysis can be extended to systems where the cross-sectional area varies with height. The specific scope of the invention, as well as the modifications, variations and equivalents of the embodiments and other examples, are included in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a molten glass manufacturing apparatus according to an exemplary embodiment. FIG. 2 illustrates analytical geometry used in performing bending analysis due to pressure on one side of a belt body. Figures and various definitions. Figure 3 shows the geometry of the geometry used in the chimney effect analysis. p^4 va/ collision j 〇 Figure 4 is the calculated pressure curve obtained by the step temperature difference between the bands (dotted line). Line), the step temperature difference is located at the bottom of the shell (stretching tower) β Figure 5 repeats the calculated pressure curve (solid line) of 帛4®, and also shows the gas density difference obtained by the step temperature difference. ° 22 201100338 Figure 6 is the calculated pressure curve (solid line) of the second DDZ obtained by the first step of the rise and then fall of the half-gap step (dotted line), the first step temperature difference system Located at the bottom of the casing (stretching tower) and the second step temperature difference is in place: above the first step temperature difference. Fig. 7 repeats the calculated pressure curve (solid line) of Fig. 6, and also shows the difference in gas density obtained by the step temperature difference. Figure 8 shows the temperature generated by the difference in gas flow rates on both sides of the strip.

Difference (dotted line) A calculated pressure curve (solid line) of one of DDZ obtained between the strips. Fig. 9 repeats the calculation of the pressure curve (solid line) of Fig. 8 and also shows the difference in gas density obtained by the difference in gas flow rate. [Main component symbol description] 3 Isolation tube 5 Tank 7 Carcass 9 Melting glass 11 Root 13 Strip body 17 Wall 19 Sheet separating device 21 Restriction 23 Housing 25 First subspace 27 First subspace 29 Internal space 31 Bottom 23

Claims (1)

201100338 VII. Patent application scope ··•• A method for controlling the arc of a vertical glass ribbon made by the pull-down procedure, including the following steps: (a) passing the belt through an inflation vertical a housing, wherein: (1) the housing includes a wall defining an interior space, (η) the bottom of the interior space is open such that the pressure at the bottom is the dust of the surrounding atmosphere, and Q (111) The strip body serves as a partition which divides the inner space of the housing into a first subspace and a second subspace; (b) by (i) on the side of the first subspace of the strip Between the average density of the gas and (ii) the average density of the gas on the second subspace side of the strip, a difference obtained above a vertical region of the length of the housing, in the first subspace Forming a positive pressure difference with the length of at least a portion of the housing in the second subspace, wherein an average D density on the first subspace side of the strip is less than the second sub The average density on the space side, and (c) limit the edge of the strip to avoid Etc. into the edge region of the vertical over at least a second sub-space. 2. The method of claim 1, wherein the difference between the average densities of the gases on the first and second subspace sides of the strip is above the vertical region, The result of a difference in composition of the gases above the vertical region on the first and the 24th 201100338 two subspace sides of the strip. 3. If you apply for a patent scope! The method of the present invention, wherein the difference between the average density of the gases on the first and second subspace sides of the strip, the difference above the vertical region, is in the strip a result of an average temperature difference between the first and first subspace sides of the gas above the vertical region, wherein the average temperature on the first subspace side of the strip is greater than the strip The average temperature on the side of the second subspace. 4. The method of claim 3, wherein the average temperature difference is the average temperature of the inner surface of the housing wall on the first subspace side of the strip, and the strip The average temperature of the inner surface of the housing wall on the second subspace side of the body, an average temperature difference Q 〇5 in the vertical region along the inner circumference of at least one section of the housing. The method of claim i, wherein between the average densities of the gases on the first and second subspace sides of the strip, the difference above the vertical region is in the strip As a result of the difference in average flow velocity of the gases on the first and second subspace sides of the body above the vertical region, the average flow rate of the gas on the first subspace side of the strip is less than The average flow rate of the gas on the second subspace side of the strip. 25 201100338 6. The method of claim 5, wherein the speed difference is a result of a difference in the amount of gas leaving the sub-space to the ambient atmosphere at a position above the mid-plane of the vertical zone. The method of claim 6, wherein the difference in the amount of the gas leaving the ambient atmosphere from the two sub-spaces is at a position above the intermediate plane of the vertical zone, The result of at least one aperture formed in the housing wall on the second subspace side of the strip. 26